The Battle of Beaver Dams took place on 24 June 1813, during the War of 1812. An American column marched from Fort George and attempted to surprise a British outpost at Beaver Dams, billeting themselves overnight in the village of Queenston, Ontario. Laura Secord, a resident of Queenston, had earlier learned of the American plans, and had struck out on a long and difficult trek to warn the British at Decou's stone house near present-day Brock University. When the Americans resumed their march, they were ambushed by Native warriors and eventually surrendered to the commander of a small British detachment. About 500 Americans, including their wounded commander, were taken prisoner.

On 25 May 1813, the Americans had won the Battle of Fort George, capturing the fort. The British fell back to a position at Burlington Heights near the western end of Lake Ontario, briefly abandoning the entire Niagara Peninsula to the Americans. The Americans attempted to pursue the British, but their advance was checked at the Battle of Stoney Creek by a British counter-attack. At the same time, the American flotilla of warships which had been supporting their army on the Niagara Peninsula was hastily withdrawn to face a threat to their own base, and a British flotilla threatened the Americans' line of communications. The Americans fell back to Fort George. The British followed up and established an outpost at DeCou's house in the present-day city of Thorold, Ontario, from which Natives and militia harassed American outposts.

The American commander at Fort George, Brigadier General John Parker Boyd, decided to clear the threat posed by enemy raiders and to restore his men's morale by making a surprise attack on the outpost at DeCou's.

The American force assigned to the attack was led by the recently-promoted Colonel Charles Boerstler of the 14th U.S. Infantry[6] and consisted of Boerstler's own 14th U.S. Regiment of Infantry, with detachments of the 6th, 13th and 23rd U.S. Regiments of Infantry, a company of artillery with one 12-pounder and one 6-pounder field guns,[7] and twenty U.S. Dragoons. An irregular corps of forty mounted volunteers from the New York Militia under Cyrenius Chapin led the way.[8] The force was accompanied by two large supply wagons. At dusk on 23 June, Boerstler's force moved in secret from Fort George to the village of Queenston, where they quartered themselves in the houses and other buildings

A Canadian tradition is that several American officers had earlier billeted themselves in the house of Militia Captain James Secord, who had been severely wounded the previous year at the Battle of Queenston Heights. His wife, Laura Secord, overheard the American officers discussing their scheme. Very early on 22 June,[9] she set out to warn the British at DeCou's house, walking about 17 miles (27 km) [10] through the woods until she came upon a Native encampment on the Twelve Mile Creek. The warriors took her to Lieutenant James FitzGibbon, who commanded the British outpost. The information she conveyed to FitzGibbon confirmed what Natives had reported since they first observed the American column near St. David's.

The main contingent of Natives were 300 Kahnawake, also referred to as Caughnawaga in contemporary accounts. (The Kahnawake were Mohawks who had earlier been converted to Christianity by Jesuit missionaries.) They were nominally commanded by Captain Dominique Ducharme of the Indian Department, with Lieutenants Isaac LeClair and J.B. de Lorimier. There were also 100 Mohawks under Captain William Johnson Kerr. They set up ambushes in a thickly wooded area 1.5 miles (2.4 km) east of Beaver Dams. FitzGibbon with 46 men of the 49th Regiment of Foot was in reserve.

Early on 24 June, the Americans climbed what locals have always called "the mountain" at St. David's, and proceeded along the Mountain Road leading to the Beaver Dams settlement. As they approached Ten Mile Creek, they became aware of Natives closing in on their flanks and rear, but Boerstler did not change his plans. When the Natives opened fire, Boerstler was wounded and placed in one of the wagons. By American accounts,[11] they put the Mohawks to flight and fought their way out of the woods into open fields where they could use their artillery and the Natives were not at such an advantage, although this account is not supported by other witnesses.

At this point, FitzGibbon intervened. Addressing Boerstler under a flag of truce, he claimed that the Americans were outnumbered and surrounded, and that if they did not surrender he would be unable to restrain the natives from slaughtering the entire American force. The wounded Boerstler capitulated to Major de Haren of the 104th Regiment, who had just arrived on the field with another detachment of British regulars from Twelve Mile Creek.[12]

The natives admitted to five chiefs and warriors killed, and 20 wounded,[2] although Ducharme stated that 15 were killed and 25 wounded.[3]

The American casualty report stated 25 killed and 50 wounded;[4] all of the wounded being among the prisoners, who numbered 23 officers and 489 enlisted men.[5] It was later claimed that many of the wounded Americans were killed by Mohawks.[3]

The loss of Boerstler's detachment demoralized the Americans at Fort George. From then until they abandoned the fort on 10 December, they rarely dared send any patrols more than a mile from the fort. To reinforce their fear of the Indians, there was another minor disaster on 8 July when a party from the 8th (King's) Regiment and Merritt's Troop of Provincial Dragoons, accompanied by Ottawas under Captain Matthew Elliott and other Indians under Mohawk chief John Norton, went to retrieve a chest of medicines which had been hastily buried at Ball's Farm near Two Mile Creek when the British had evacuated Fort George in May. An American party from the 13th U.S. Infantry under Lieutenant Joseph Eldridge attempted to pursue the British detachment but was ambushed, losing 28 men, several of whom were scalped despite the efforts of officers of the Indian Department to prevent it.[13]

Most of the American regular soldiers and Boyd himself were transferred from Fort George to Sackett's Harbor in September, leaving the fort in the hands of New York Militia.

Referring to the respective parts played by the various Native Americans and the British, local legend (perhaps started by Mohawk leader John Norton, who was present) had it that, "The Caughnawaga got the victory, the Mohawks got the plunder and FitzGibbon got the credit".[2][14]

In 1818,[2] FitzGibbon made a report to Captain Kerr which read in part:

With respect to the affair with Captain (sic) Boerstler, not a shot was fired on our side by any but the Indians. They beat the American detachment into a state of terror, and the only share I claim is taking advantage of a favorable moment to offer them protection from the tomahawk and scalping knife. The Indian Department did the rest.[12]

Captain Ducharme claimed that he himself did not demand the Americans' surrender because as a French Canadian by birth who had spent most of his life among the Indians, he spoke no English.[13]

I do hereby Certify that on the 22d. day of June 1813, Mrs. Secord, Wife of James Secord, Esqr. then of St. David's, came to me at the Beaver Dam after Sun Set, having come from her house at St. David's by a circuitous route a distance of twelve miles, and informed me that her Husband had learnt from an American officer the preceding night that a Detachment from the American Army then in Fort George would be sent out on the following morning (the 23d.) for the purpose of Surprising and capturing a Detachment of the 49th Regt. then at Beaver Dam under my Command. In Consequence of this information, I placed the Indians under Norton together with my own Detachment in a Situation to intercept the American Detachment and we occupied it during the night of the 22d. – but the Enemy did not come until the morning of the 24th when his Detachment was captured. Colonel Boerstler, their commander, in a conversation with me confirmed fully the information communicated to me by Mrs. Secord and accounted for the attempt not having been made on the 23rd. as at first intended.[15]

By this account, Laura Secord learned of the American plans and made her exit from St. David's (near Queenston) on 22 June, before the American main body had set out from Fort George.

Beaver Dams represents one of the earliest attempts to create a national historical park. In 1914, a convention of Ontario historical and patriotic groups resolved to ask the Department of the Interior "to develop a 40-acre site near Thorold as a national battlefield park commemorating the Battle of Beaver Dams."[16]

Although Beaver Dams was not made a national park, the Historic Sites and Monuments Board was created in 1919 to develop a heritage policy at the federal level for historic sites. In 1921, soon after the Board's formation, the Board recommended the designation of the Battle of Beaver Dams site as a National Historic Site of Canada, one of its earliest selections.[17][18]

A monument commemorating the battle was dedicated in 1923 and situated on the original site of the event (near the southeast corner of the intersection of Davis Road and Old Thorold Stone Road,[19] approximately 1.4 kilometres (0.87 mi) southeast of present-day Thorold), where it was located for several decades. In 1976, this monument (as well as one marking the site where in 1876 during construction of the 3rd Welland Canal the remains of 16 U.S. soldiers from the battle were uncovered) was subsequently relocated several kilometers to the west when the Battle of Beaverdams [sic] Park was opened and there was talk of constructing a 5th Welland Canal near the battlefield. The original site of the battlefield is currently unmarked,[20] although there is bicentennial talk of marking it with a "historic boulder".[19]

^Clarence M. Warner, president, Ontario Historical Society, to William J. Roche, Minister of the Interior, July 3, 1914. Cited in C.J. Taylor, Negotiating the Past: The Making of Canada's National Historic Parks and Sites, 1990, p. 30. The Dominion Parks Branch was under the jurisdiction of the Department of the Interior.